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Manual Pages for UNIX Darwin command on man gets

FGETS(3) BSD Library Functions Manual FGETS(3)

NAME

ffggeettss, ggeettss - get a line from a stream

LLIIBBRRAARRYY

Standard C Library (libc, -lc)

SYNOPSIS

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char * ffggeettss(char * restrict str, int size, FILE * restrict stream); char * ggeettss(char *str);

DESCRIPTION

The ffggeettss() function reads at most one less than the number of characters specified by size from the given stream and stores them in the string

str. Reading stops when a newline character is found, at end-of-file or

error. The newline, if any, is retained. If any characters are read and there is no error, a `\0' character is appended to end the string. The ggeettss() function is equivalent to ffggeettss() with an infinite size and a stream of stdin, except that the newline character (if any) is not stored in the string. It is the caller's responsibility to ensure that the input line, if any, is sufficiently short to fit in the string.

RETURN VALUES

Upon successful completion, ffggeettss() and ggeettss() return a pointer to the

string. If end-of-file occurs before any characters are read, they

return NULL and the buffer contents remain unchanged. If an error occurs, they return NULL and the buffer contents are indeterminate. The

ffggeettss() and ggeettss() functions do not distinguish between end-of-file and

error, and callers must use feof(3) and ferror(3) to determine which occurred. EERRRROORRSS [EBADF] The given stream is not a readable stream. The function ffggeettss() may also fail and set errno for any of the errors specified for the routines fflush(3), fstat(2), read(2), or malloc(3). The function ggeettss() may also fail and set errno for any of the errors specified for the routine getchar(3). SSEECCUURRIITTYY CCOONNSSIIDDEERRAATTIIOONNSS The ggeettss() function cannot be used securely. Because of its lack of bounds checking, and the inability for the calling program to reliably determine the length of the next incoming line, the use of this function

enables malicious users to arbitrarily change a running program's func-

tionality through a buffer overflow attack. It is strongly suggested that the ffggeettss() function be used in all cases. (See the FSA.)

SEE ALSO

feof(3), ferror(3), fgetln(3), fgetws(3) STANDARDS The functions ffggeettss() and ggeettss() conform to ISO/IEC 9899:1999 (``ISO C99''). BSD June 4, 1993 BSD




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